The poliovirus enters the human body through
a. Mosquito bite
b. Tick bite
c. Saliva and secretions from the nose
d. Contaminated food and water

Hint: Poliomyelitis in a short form we called it as polio, it is an infectious disease caused by the poliovirus, where it enters the person through the mouth, from the gut of the person it enters the central nervous system, where it causes muscle weakness and result in flaccid paralysis.

Complete answer:
- Polio mainly spreads from one person to another through infected fecal matter that enters the mouth, it may also through contaminated water and food with infected human feces, and rarely it is spread by infected saliva.
- Polio is caused by the poliovirus which belongs to the genus Enterovirus, where it enters through the mouth, and it is incubated in the oropharynx from 3 to 35 days, and it may enter the central nervous system.
- But if the people are vaccinated by the poliovirus and already have the antibodies, mainly IgA antibodies they prevent the virus from entering the motor areas of the nervous system.
- Some serotypes of the poliovirus do not cause any major symptoms, while some are symptomatic, they may cause paralysis or may not, and it is called abortive poliomyelitis.
- Only 1% of the infected people show the symptoms related to CNS, where the muscle becomes weak, floppy and flaccid paralysis occur.

Hence, the correct answer is option (D).

Note: Generally the polio prevention is done by the vaccination, mainly of two types, where both provide immunity to fight with polio, and block the person to person transmission of the virus, so it protects the person individually and the community also, it is providing the herd-immunity.